The present invention relates to multithreading, and more particularly, to a method for controlling multithreading in a system that performs parallel processing with multiple threads so as to increase the speed of programs and efficiently use system resources.
In a system that executes programs, such as scientific calculations, threads are used to perform parallel processing. This increases the speed of programs. An operating system (OS) program generates threads in accordance with application programs. The OS allocates system resources to each of the generated threads and runs programs associated with the threads in a parallel manner.
It takes time for the OS to generate a thread. Thus, once a thread is generated, the thread remains undeleted so that it can be used again. This increases the system processing speed.
In more detail, when a thread completes execution of a program, the OS registers the thread as a standby thread in a table. Then, if there is a request for generating the thread, the standby thread registered in the table is used to run a program. This decreases the time for generating threads.
In the prior art, all of the generated threads are managed as standby threads. Thus, if the number of the running threads that are actually running is small, the system would have a large number of unnecessary standby threads. This wastes memory resources since system resources are allocated to the standby threads.
For example, if 200 parallel threads are run at a certain time, and then only two threads are run at a later time, 198 unnecessary standby threads would be occupying the memory. This is undesirable when operating a system that has low resources and would significantly affect the speed of other programs.